Rough notes man has penned like that for builder (10)
I believe the answer is:
stonemason
'for builder' is the definition.
(I've seen this before)
'rough notes man has penned like that' is the wordplay.
'rough' indicates an anagram (a rough or broken ordering of the letters).
'has penned' is an insertion indicator (inserted letters are enclosed or penned in).
'like that' becomes 'so' (as in 'like so').
'man' placed around 'so' is 'mason'.
'notes' with letters rearranged gives 'stone'.
'stone'+'mason'='STONEMASON'
(Other definitions for stonemason that I've seen before include "Rock craftsman" , "Person skilled in preparing rock for building etc" , "Chiseller" , "Craftsperson" , "manual worker" .)